1. Field of the Invention
The present invention relates to an expandable seal arrangement, and associated method, for sealing a gasket to an annular wall of a rigid structure.
2. Description of the Related Art
In underground pipe systems, it is often necessary to connect a pipe in a sealed manner within an opening in the wall of a rigid structure, such as a manhole riser or monolithic base, for example. Typically, a flexible elastomeric gasket is placed within the opening in the wall, followed by fitting an expansion ring against the interior surface of the gasket. Thereafter, a suitable expansion mechanism is used to radially expand the expansion ring and lock same in an expanded condition in which the gasket is sealingly compressed between the expansion ring and the opening in the wall of the structure. Thereafter, a pipe is inserted through the gasket, and one or more clamps are installed around a portion of the gasket which extends from the wall to sealingly compress the extending portion of the gasket between the clamps and the outer surface of the pipe. In this manner, a sealed connection is made between the pipe and the structure.
One known expansion ring includes a ratcheting engagement between overlapping ends of the ring. When the ends of the ring are forced in opposite directions from one another as the ring is radially expanded, ratchet teeth on the ring ends sequentially engage one another, wherein the expansion ring may be sequentially expanded in an incremental manner into multiple locked positions. A separate tool is used to engage the opposite ends of the expansion ring and to drive same apart from one another. Typically, such tools can be expensive, as same are specialized and designed for specific use only with a particular corresponding configuration of the expansion ring.
Although the foregoing expansion rings are effective, the expansion rings may only be expanded in designated increments which may not correspond to an ideal diameter of the expansion ring which is the most effective to sealingly compress the gasket between the expansion ring and an opening in the wall of the structure. For example, a suitable tool may be used to expand the expansion ring to an expanded, locked position in which the gasket is not compressed to its fullest extent between the expansion ring and the opening, yet further expansion of the expansion ring may not be possible because the gasket cannot be further compressed sufficiently to allow for expansion of the expansion ring to the next locked position.
What is needed is an expansion ring mechanism which is an improvement over the foregoing.
The present invention provides an expansion ring assembly for sealing a gasket with respect to an annular wall of a rigid structure. The expansion ring assembly includes a drive mechanism for engaging and driving apart the opposing ends of an expansion ring to thereby radially expand the ring. The drive mechanism generally includes a pair of block members having threaded bores therethrough, and a bolt having oppositely-threaded ends which are threaded within respective bores of the block members. The bolt additionally includes tool-receiving structure, such as a nut portion, which may be engaged by a suitable tool to rotate the bolt. The block members are respectively engaged with opposite ends of the expansion ring. Rotation of the bolt in a first direction simultaneously drives the block members apart from one another along the bolt to radially expand the expansion ring, and rotation of the bolt in a an opposite, second direction simultaneously drives the block members toward one another along the bolt to allow the expansion ring to radially contract.
Expansion of the expansion ring compresses the gasket between the expansion ring and the opening of the structure to provide a fluid tight seal between the gasket and the structure. Subsequently, a pipe may be inserted through a second portion of the gasket which extends outwardly of the structure, followed by securing the extending portion of the gasket to the outer surface of the pipe using conventional hose clamps or take-up claims, for example.
The present expansion ring assembly may be used in other applications, such as, for example, sealing a gasket about the interface between a manhole base and a manhole frame to prevent water infiltration into a manhole, or for sealing an internal coupling gasket within one or more pipes to prevent water infiltration into a pipeline.
Advantageously, the oppositely-threaded ends of the bolt allow rotation of the bolt in one direction to simultaneously drive the block members apart from each other to expand the expansion ring, such that only one tool need be used to actuate the drive mechanism to expand the expansion ring. Additionally, the screw threaded engagement between the bolt and the block members allows the block members to be driven away from one another along the bolt to an infinitely variable extent based upon the rotational position of the bolt. Therefore, the expansion ring may be expanded to a precise point wherein the gasket is firmly and sufficiently compressed between the expansion ring and the opening of the structure to provide a fluid tight seal.
The expansion ring may also be further expanded after initial installation, if needed, to tighten the seal of the gasket by simply engaging a tool with the bolt of the drive mechanism and rotating same to drive the block members apart from one another to further expand the expansion ring. A further advantage of the expansion ring assembly is the ability to remove the assembly from the structure if needed, followed by re-installing the assembly in a different position, or by re-using the assembly by installing same in a different structure or using same in a different application.
Additionally, a plurality of specially configured wrenches are provided, which include socket ends having a varying angular orientation, allowing a suitable socket end to be engaged with the nut portion of the bolt of the drive mechanism when the drive mechanism is in a small clearance space, regardless of the rotational position of the nut portion. Further, a wrench is provided which includes a socket end having an internal notch which facilitates ratcheting movement of the socket end of the wrench with respect to the nut portion of the bolt, thereby allowing rotation of the bolt without complete removal of the wrench from the bolt between wrench turns. The wrench may be configured with a pair of plates attached to the sides of the socket end of the wrench, which engage the sides of the nut portion to prevent the socket end from slipping off of the nut portion as the nut portion is rotated.
In one form thereof, the present invention provides an expansion ring assembly for sealing a gasket to an annular wall, including a ring defining a pair of end portions; and a drive mechanism, including a pair of block members each having a threaded bore therethrough, the block members removably engaged with respective end portions of the ring; and a bolt including oppositely-threaded ends respectively threaded within the bores of the block members, wherein rotation of the bolt in a first direction causes the block members to be simultaneously driven apart from one another to thereby expand the ring.
In another form thereof, the present invention provides, in combination, a structure having an annular wall; a flexible, substantially annular gasket received within the annular wall; and an expansion ring assembly received within the gasket, the expansion ring assembly including a ring defining a pair of end portions; and a drive mechanism including a pair of block members each having a threaded bore therethrough, the block members respectively engaging the end portions of the ring, and a bolt including oppositely-threaded ends respectively threaded within the bores of the block members, wherein rotation of the bolt in a first direction causes the block members to be simultaneously driven away from one another to thereby expand the ring and compress the gasket into sealing engagement with the annular wall.
In another form thereof, the present invention provides an expansion ring assembly in combination with a gasket for outwardly radially compressing the gasket into sealing engagement with an annular wall, including a ring defined by at least two segments, each segment having a pair of opposite end portions; and at least two drive mechanisms, each drive mechanism including a pair of block members each having a threaded bore therethrough, the block members respectively associated with adjacent end portions of the ring segments; and a bolt including oppositely-threaded ends respectively threaded within the bores of the block members, wherein rotation of the bolt in a first direction causes the block members to be driven away from one another to thereby expand the ring.
In a still further form thereof, the present invention provides a method of sealingly connecting a gasket to an annular wall, including the steps of placing a gasket within the annular wall; fitting an expansion ring against an interior surface of the gasket; engaging a tool with a bolt of a drive mechanism, the bolt including oppositely-threaded ends threadably engaged with block members associated with opposing ends of the expansion ring; and rotating the bolt with the tool to simultaneously drive the block members apart from one another to expand the expansion ring and sealingly compress the gasket between the expansion ring and the annular wall.
In a still further form thereof, the present invention provides a wrench for use in engaging a nut, including a shank having an open socket end profile with at least two surfaces configured to engage corresponding surfaces of the nut; and a pair of side portions which project beyond the open socket end profile, wherein when the wrench is engaged with the nut, the side portions prevent lateral separation of said wrench from the nut.